1. Field of the Invention
The device of the present invention generally relates to hermetically sealed gas tube voltage breakdown devices, commonly referred to as surge arresters, and, more particularly, to a new and improved hermetically sealed gas tube surge arrester having a faster response time to impulse voltage surges.
2. Description of the Prior Art
Hermetically sealed gap tube voltage breakdown devices, commonly referred to as surge arresters, are old and well known in the art and are often used to protect electrical equipment from damage or destruction due to the presence of overvoltage surges. For example, pertinent prior art hermetically sealed gas tube surge arresters are disclosed in U.S. Pat. Nos. 3,588,576; 4,084,208; and 4,287,548.
Normally it is desirable that the sparkover or breakdown voltage of hermetically sealed gas tube surge arresters be independent from the rate of surge voltage increase, that is, dV/dt. While this is generally true with respect to known surge arresters for rates of surge voltage increase up to approximately 10.sup.6 volts per second, the impulse breakdown voltages for such surge arresters for rates of surge voltage increase above approximately 10.sup.8 volts per second are generally considerably higher than their DC or static breakdown voltages. The prior art patents referred to hereinabove describe attempts that have been made to reduce the difference between the impulse breakdown voltage and the DC breakdown voltage in a surge arrester and the variations in the impulse breakdown voltages resulting from impulse voltage surges having different rates of voltage increase. This problem is also addressed by the present invention.